As it is generally known, the phrase “Web 2.0” refers to a new generation of Web-based services that emphasize online collaboration and sharing among users. Social bookmarking is thought of as a key Web 2.0 component. In a social bookmarking system, a social bookmarking Web site provides a mechanism for users to store, classify, search and share links (i.e. hyperlinks) as bookmarks. Users can save lists of bookmarks that may be shared or kept private. Users bookmark resources (e.g. Web pages) that are meaningful to them, and associate tags with bookmarks to create a folksonomy. A tag can be a keyword or label of some kind. The act of sharing bookmarks and tags makes such systems social in nature. Bookmarks in a social bookmarking system may be shared with the public, or with a network of users (also known as the social bookmarking “community”). For purposes of explanation herein, the term “bookmark” is used throughout to refer to a bookmark defined in a social bookmarking system, and that accordingly may be either private or shared.
Existing social bookmarking systems support resource categorization based on freely chosen, user-defined keywords (“tags”) that may also be shared with the public or a user network. These systems generally allow users to search for bookmarks associated with a selected tag, and also operate to rank bookmarked resources based on the number of users that have bookmarked them.
The collection of tags applied to Web pages bookmarked in a social bookmarking community may be used to generate a structure of associations referred to as a “folksonomy”. The primary characteristic of a folksonomy is that it is user-defined. Accordingly, unlike a taxonomy, which operates using a fixed vocabulary, a folksonomy has an open-ended vocabulary, evolving based on tags freely chosen by end-users. A folksonomy represents relationships between bookmarks and user defined tags, and may also represent relationships of users to tags and to other users. Folksonomies may also allow derivation of the relationships between tags. The socially relevant information available in a folksonomy is considered to be a great asset. The immediate feedback that can be derived from this information motivates end users to tag more bookmarks, and supports effective browsing for desired content. Tags are useful for searching and sharing bookmarks. Users can use the tags that are already defined for a bookmark, or create their own.
Despite all the benefits of existing folksonomies, some shortcomings arise relative to traditional taxonomies. The frequent use of different terms having similar or identical meanings, different stems of the same term, and differences in case, all may result in ambiguities that don't exist when the tag space is fixed (e.g. defined in a controlled vocabulary that cannot be extended by end-users). These ambiguities may inhibit effective and efficient information discovery, and there is accordingly a critical need for end users to communally express the relationships between such semantically related terms to overcome such limitations.
Existing social bookmarking applications have attempted to address ambiguities in folksonomy data using various techniques. One approach has been to provide guided tagging of bookmarked resources. End users are prompted to reuse previously defined tags in order to prevent the unknowing creation of multiple tags that are trivial variants of one another, and/or the use of uncommon spellings of tag terms. To this end, as a user begins to enter a newly defined tag, a set of previously defined tags that match the entered letters are displayed, e.g. sorted in an order reflecting frequency of previous use. Along this same line, some existing systems provide a list of popular tags used by others who have bookmarked the Web page that the new tag will be associated with. This approach, although enabling end users to tag with greater consistency, does not deal with ambiguities that nevertheless do arise in the tag space, because of inconsistencies in spelling, synonyms, and varying stems. Similarly, systems providing auto-completion assistance to users entering new tag terms fail to address the use of synonyms with completely different spellings as different tags.
Some existing systems have used case insensitivity to address problems of tag ambiguity and inconsistency. Systems such as del.icio.us allow end users to define tags in upper and/or lower case characters, but provide case insensitive tag browsing. This enables end users to browse bookmarks even when they are tagged with differing case tags, without restricting the ability of end users to freely choose the way their own tags are displayed. However, this only solves a small piece of the overall problem, and does not address the more significant problems arising from the use of tags that are synonyms, misspellings, varying stems, and/or differing word concatenations or combinations. Some existing systems (e.g. del.icio.us) allow end-users to create tag bundles that visually represent logical groupings of tags in the user interface. In such systems, a user might cause similar tags to be displayed together under a label that makes sense to that user. However, the tag bundles provided by existing systems are for the individual end user only, are not social in nature (i.e. not shared), and are used only to provide labeled visual grouping of tags in the end user's user interface. When browsing among the tags in a bundle, only individual tags displayed within the bundle can be selected by the user (i.e. clicked on), and thus the user may still be required to navigate each individual tag in the bundle to find the desired bookmarks.
The Flickr photo sharing Web site provides tag “clouds” that visually represent tag sets, in which more frequently used tags in the set are depicted in a larger font or otherwise visually emphasized. Selection by the user of a single tag produces a number of tag clusters that are closely related. The clusters help users navigate related tags based on the underlying meaning of a term. This approach assists in distinguishing bookmarks based on the intended meaning of a tag, but does not aid in dealing with variations on a single tag (i.e. case, stems, similar terms, concatenation of terms etc.), since these groupings are based on how frequently two tags are used in a single bookmark.
For the above reasons and others, it would therefore be desirable to have a new system for providing collaborative tag sets to assist navigation of a folksonomy.